Bar joist



T. A. LUCY Sept. 20, 1932.

BAR JOIST Filed NGV. l5, 1929 @m1/bow 2- 72/0M45 -14 40er, bMMw/QVW f Figf is a detail Patented sept. 2e, 1932 'UorsfooMrANY, oFBmMINeHAMgALAB-mvm p f' gAppntiqa medivovempriaiezeffseielplv. 51073310.'ifi"v This invention pertains' fbaiiaiig units commonly kno-wn as bar joistsi Such la unit `o on'iprises lan assemblage ofr'ods orilbalrs made] p in the 'form ofia truss and adapted to serve'asajoist forbnildings... 1 'Y '7 9 Anotherobject provide a construction in whichV members of thejoist are interlooled insuch a Ywayas to more seorelysupport the forces eXertedbyseh members;V

Anothery objeetis' toi-,provide improved means for'seouring Vthe `j'oist to vits supports.

`Anotherobj`eotisfto providea Construction 4in which the forces ative inthe joistare bal- V220 anced withrespeot to :its-'axial plane. f

' *Anotherobjeots to provide a` Constructiony in which the end panel ofthe trss isstrengthsembling the elements Vofthe'j oist preparatory to-welding'thesame together; this view showingonlyone half of they joistalongthelon gi- 4tudina'l Center linefthereof T- l l Fig isa sec-tiononlne'Bf-SiFigJl ;V l

p section Q'taken along. line Fig. is'a'detail'illustratingthe manner in which theweb members arelsecured'to the top Achordg'- Y l' Y manner ofseoliringthe'joistto its supports;

- angle bars l, so plaoed that one flange' ofeaeh angle'is' horizontalandform's the upper bear- *ing-surface" ofthefjoi'st. Theotherangeof Peaohangle extends downwardly and` thesetwo "downwardly ext'endingftlangesare positioned invention Y provide method ofoonstructingab'ar )01st by which greater' strength and rigiditymay Y Further objects appear from the'detail fr rig; f6 is Y detail; side view; ehewing the aocordanoe with this invention the 'up-5 -fperchord ofthe joist is Jformed of a pair 'of on kthe insideA ofthe chord 4or' facing one an! other as shown 'in FigQSj- The lower chord` p reonsistsV of a pair of rods 2. The web of theV joist is` made np ofaseries ofunits each com-V prising a bentrodprovidngma'itension mem- B5.

ber andaoompression member or strut4'.*- n

'lhese'element's arelassernbledY as shownin Fig. 25 whiohfrepresents a view taken through`l the :center of the trusswith one halffof eaoh gw" of ,the 'upper Vandy lower -chordsand half of ifm 4 theend-'bearing member removed. The'web units aire-placed in Iposition as shownwithf- (thebend between'therods of theflower chord y Vand both upper ends between the, verti'oalM Y *flanges of, the angles v 1 of the uppericllord 85 v' The-'webmembers are then secured to the ohordmembersbyweldingl In welding the upper ends offh'ejwe'b fni- 'Y terloekingconnection.l l'.[hejinterloolred ends 'i are then f'Sepured-'es beth angle' bars er' the f `upper Chord lby Covering the 4same with Weldingmetal las indioatedin Fig'f.V rlhnsthel` imembers 31a-nd 41: are not only 'interlooked with oneanotherv lbut are securely Vwelded, to the, upper chord. v lowerends ofthe web members are welded'at 6 of the lower Chord.:

In'order toprovide an endbearing iorthe `85 )oist apair of angle' bars'?` 4is'placedbaok to back .with adjacent flanges engagingl one v another "andfextending :between the endsfgof the vertical langes of the,upperfohordmembers` l; as illu*strated in `lpig. 43,v The otheriflanges 90 Y l.8 .ofthe` member 7 `extend horizontally' to xi vform 'a bearing faoeadapted to reston the supportnpOLWhioh the lioist is placed.'l TheV members V.7 arewelde'd to the upper chord;

"members l, lmoll the-ends of the lower Chord i membersfarefbent upwardly vand weldedjto'y.V i

Vthe"members Tat-the inner corner thereoi'asl v indioatedinv Figsir and 4:

' Irrorder to strengthen the end section of; l i i' Y* the oist, the tension member 30 of' the lasst:`

open ends are left straight until Laifterthe anchor has been placed in position. The anchor is applied by placing the bight T1 engagement with thenotch 9.asindicated in Fig. 6. The free ends of the anchor extend over `the yedge of the supportingzelement :l2 'whichacarries the joist. The .element x.12may be a :girder'or wall or arryfother support .on

`which'the oistsareiplaced. Thefree endsof the' anchor l0 are thenbent downwardly over the edge of .the supportsoeas1to=secure :the latter against slipping zon .the support.

.Another way -of :anchoring Ithe joist .is lto provide notches .13 .1in :the rearedges of the lhorizontalfflanges 'of-thexmembers 7', as'shown in Fig. 4. A pair ofstraight anchors may then 'be` hooked into 'these notches and Vbent over the edge of .the support, :as shown in Fig. -1. I ft twill be seenftherefore, fthat this .inven- .tion.accomplishes-itsobjects. A joistisiprovided which is veryistrongandrigid and in which .the forcesare balanced-iabout-its axial plane. The upper and-lower chord members arefsymmetrical with respect Vto `said plane 'andthewebzmembers are allplaced centrally `between-thefupper and lower chord members soasto .lie inthe 'axial plane. Accordingly, there -willbe `no tendency .fortherj oist to .twist 40 orbuckleunderload, Y

The method `of securing ythe .-webj members `as illustrated inEig. v5, formsa .securein'ter- .lock in which vthe fcompression forcefof the strut .Klis brought. directly. against `thetension 45. .of the 'memberf This.constructionrelieves the welded :joint of `a great deal .of lload `on .these members. The construction illustrated in Fig. 3 .provides anarnplebearing for the oist oniitssupportf and alsoprovides 50 .a-very .rigid end .capable of resisting .distorting strain. .The arrangement ofthe extra tension .memberBO strengthensitheend panel of ftheftruss at .a point .where .most trusses ofthis typeare weak. T he anclionconstruction `:illustrated in .'Fig. 16,. not :only securely .anchors the oist .to fits :support .but applies a supporting anchorage near .the upper vextremityof .the joist so. as .toreduce the .positive stresses at the .center .thereof .Since 1:50 the anchor 10 issecuredrto theuweb ofthe bearingmemberrat a.,point`near the upper. eX-

tremitythereof, andin factjust belowtheupper chord, it is inpositiento' exertatension `in theupper part ofthej oist. 'W hen. the]l oist '165 isput under load .there;is,` of course,ra;tend

ency to sag and the upper chord has a compressive stress produced therein. The tendency to sag. at the same time tends to draw the upper portion of the joist at its ends over the supports 12 inwardly toward the middleiof the truss. Inother words, there iis :a A'tendency to tip .that part Lof ithe joist shown in Fig. 6 to the right. This tendency is resisted by the anchor `10 which exerts a -tensionin Ithe opposite ldirection. Y This tension isiapplie'd -nearthe upper extremity of the joist and along the upper chord. If the above mentioned compressive stress is considered 4positive, this tension induced by "the anchor will'be negative and thus tend to :reduce .'the .positive :compressive: stress: acting iin'thefupper chord.

While `this truss has fbeen described -as a lunitary structure, it ewill-ifbe Yunderstood-thatindividual features, .or sub-combinations thereof, are -useful 'without ireferencetmother parts :of the structure and ithat lthe *use of such features `or subcombinations isfeontemplated by this invention, and is .Withinthe :scope ofthe appendedclaims.

It is .obvious .that various @changes may .be :made in details of construction, within lthe scope of the :appended rclaimfs, without Adeparting fromthe-spiritmf.- thisinvention. It is, therefore, :to "fbe understood that this iin- Yvention :is inet `to be limited .to thesspecific details .-shownsand /or described.

'Havingsthus .described -the'inventiom what l claim is:

l. A bar gjoist comprising, -anupper chord, fmember,.a web secured-thereto,fa,pairiof lower Achord members secured ito .said vweb .on opposite sides thereof, a bearing membenseycured .to said upper chord member at the .end thereof, and -a .looped .anchor :member engageable lwith said bearing--member .near the upper extremity of.said.membersatthe bight of its loop with .itsends-:extendingbeyond the Yend of :the j oist 'to Abe Ibent '.on a support.

l2. .A bar .joist having; achordmembenand a yweb :including 4.tension and compression members, characterized Y'by the feature f' that the endfof said f tension imember :is bent'over Vthe end of .said -compression .member iand 'i welded to said chord member.

8. :Abar joist, .comprising,.a ;pair of Lupjper .chord members, .a .pair rof .lower ichord members, and a plurality of separate .web .units each dormed to; provide atensionmem- .ber .and a :compression .member, .said web units being lsecured to said chordmembersbetween members ofaxpair.sothattheiendiof a compression member .of V.one .of .said Aunits .receives andv supports the tension membenof .an adjacent unit.

l. A `bar joist, comprising,.avpairrof-upper chord members, axpair oflower .chord members, and a plurality of -web units reach formed to provide :a .tension 'member and a "1,878,281 In?. j' l l 3 compression member, ksaid web units being welded to said chord members between `I nemy bers ofapair so'thattheend of a compression member of one of said units interlockswith Y 5 the tension member of an adjacent unit at '.suchweld" .Y- Y

5. In the art vof making bar joists, they Y Y methodfcomprising, assemblin "a, chord .49 9. In a bar j'oist, alweb panel'unit com-` i i 55 this 25th v day offOctober-,-1929L- member with a plurality of we (members, 10 heating the vend of oneof said web members so kas to bend the sameover the endof ani other web member to interlock said members, 'Y and welding said web members to said chord member at said bend.' j i if; 15 6. In the art of making bar joists,the1meth` I od comprising, assembling a chord member Vwith a plurality of vweb members, heating the end of one ofsaid webmembers Y so as to `bend Vthe'same over the end ofjanother web member, to interlockl saidY members, welding saiddweb membersk to said Vchord member at saidbend, and depositingthe welding metal to cover said interlocked ends.4 d

7. A bar oist,comprising, upper andlower chords, a webmember secured toand con- --vnecting said chords, a bearing member securedto said upper chord at the end thereof, Y and an-anchor engaging saidbearing mem- Y ber near its upper, eXtremity and inwardly of its bearing portion adapted for connec`-. VY i .tion toa support.`

8. Abarjoist, comprising-,`upper and lower chords, a web member secured to and connecting said chords, a bearing member securedY to said upper Chord at the end thereof s and having a recess near'its upper extremity j at its inner end, and fanjanchor engaging said recess and adapted for connectionto a support.

` tprisinga bar bent to form* a single upright Y strut member,V and a single inclined tension member, one of saidjmembers beinglformed` `V `tointerlock withfthe other'lmember of an 45 adjacent panel. f y; d 10. In a bar pjoist havingupper and lower v chords, a web panel unit `comprising;asingle Y Yupright strutl member fand-fasingle inclined tension member, said members being formedy fV so to interlock at the junctions of adjacent'pan- "i els, and means securing said panel elements `to said chordsLQ SW im In Vtestimony whereofI aixmygsi'gnaturej THOMAS @LUCY i 

